Abe 2020 | Japan | cross-sectional | 1794 | m = 949, f = 845 | 9–15 | questionnaire | The average ST length ≥ 2h/d accounted for 97.1%. | |
Namanjeet 2018 | The United States | cross-sectional | 3421 | | 6–11 | questionnaire | The average ST length ≥ 2h/d accounted for 72.4%. | TV and computers |
Hmidan 2020 | Arab | cross-sectional | 1023 | | 9–12 | questionnaire | Average ST of watching TV/DVD/videos ≥ 2h/d accounted for 34.8%; using computers ≥ 2h/d accounted for 17.0%; playing video games ≥ 2h/d accounted for 16.5%; using mobile electronic devices ≥ 2h/d accounted for 21.5%. | TV / DVD / Video, computers, video games, mobile electronic devices |
Hila Beck 2021 | Israel | cross-sectional | 1758 | m = 826, f = 932 | 11–17 | database questionnaire | The ST behavior of most children exceeded 2h/d (higher-income families: 60.83%; non-high-income families: 63.91%). | TV and computers |
Bucksch 2019 | Germany, Poland, Slovenia, Czech Republic | cross-sectional | 18781 | m = 9295, f = 9486 | 11,13, 15 | database questionnaire | The total average ST length of the study population ≥ 3.5h/d accounted for 67.7%. Average ST ≥ 3.5 h/d accounted for 69.4% in Czech Republic; 66.6% in Germany, 71.4% in Poland and 61.1% in Slovenia. | TV and computers |
Kar 2021 | Australia | cross-sectional | 127 | m = 54, f = 73 | 10–13 | database questionnaire | Average ST ≥ 2h/d accounted for 67.7%. | entertainment purposes |
Guo YF 2021 | China | cross-sectional | 10416 | m = 5219 f = 5197 | 10–16 | online questionnaire | During the COVID-19 pandemic, average ST less than 2h/d accounted for 31.6%. | learning and entertainment purposes |
Lilian 2019 | Berlin | cross-sectional | 2122 | | 12–13 | questionnaire | Average ST less than 2h/d accounted for 81.5%. | TV and computers |
Giacomo 2018 | Italy | cross-sectional | 3291 | | 11–15 | questionnaire | Average ST of watching TV ≥ 2/d accounted for 46.4%; playing games ≥ 2/d accounted for 29.2%; using computers ≥ 2/d accounted for 38.8%. | TV, games, computers |
Lin YC 2020 | Taiwan, China | cross-sectional | 1005 | m = 503, f = 502 | 6–13 | questionnaire | Average ST > 2h/d accounted for 54.9%. | computers and TV |
Kwok 2018 | Europe | cross-sectional | 61329 | m = 27832, f = 33497 | 11,13, 15 | database | Average ST length of boys > 2h/d on weekdays accounted for 62% and that among girls > 2h/d accounted for 59%. Average ST of boys at weekends > 2h/d accounted for 79% and that among girls > 2h/d accounted for 77%. | computer games and TV |
Natalie 2017 | UK | cross-sectional | 527 | m = 253, f = 274 | 11–12 | questionnaire | Average ST > 2h/d accounted for 69.7%. | TV / DVD |
Monserrat 2020 | Spain | cross-sectional | 402 | m = 216, f = 186 | 2–14 | questionnaire | Average ST ≥ 2h/d among children aged 6–14 accounted for 60.6%. | TV and games |
Silveiraa 2020 | Italy | cross-sectional | 1200 | m = 545, f = 655 | 6–17 | questionnaire | Average ST of children (34.3%) and adolescents (48.2%) was ≥ 2h/d. | |
Neto 2021 | Brazil | cross-sectional | 1438 | m = 675, f = 763 | 10–14 | questionnaire | Average ST > 2h/d accounted for 59.6%. | computer, TV and games |
Konstantinos 2020 | Norway | cross-sectional | 177091 | m = 90821, f = 86270 | 8–17 | database questionnaire | Average ST ≤ 2h/d accounted for 65.4%. | computer, non-learning purposes, mobile phones, TV, games |
Hiromasa 2018 | Japan | cross-sectional | 1374 | m = 679, f = 695 | 6–15 | questionnaire | Average ST of watching TV among boys < 2h accounted for 58.6% and that among girls accounted for 56.6%. | TV, computer and mobile phone |
Wang LM 2021 | China | cross-sectional | 1585 | m = 811, f = 774 | 6–14 | questionnaire | Average ST > 2h/d accounted for 57.5% among 6–7 years old, 57.1% among 8–10 years old, and 47.6% in middle school (11–14 years). | computer, tablets and mobile phones. |
Lucy-Joy 2018 | Kenya | cross-sectional | 563 | m = 262, f = 301 | 9–11 | database questionnaire | Average ST < 2h/d on school days accounted for 67.9% and average ST < 2h/d at weekends accounted for 25.8%. | |
Wang SJ 2020 | China | cross-sectional | 111173 | | 10–14 | database questionnaire | Average ST < 2h/d on school days accounted for 66.8% and the average ST length < 2h/d at weekends accounted for 38.4%. | |
Yan HY 2017 | China | cross-sectional | 2625 | | 7–12 | database questionnaire | The average ST length > 14h/w accounted for 35.43%. | TV, video games, social networking sites, videos, search for news and learning materials |
An MJ 2018 | China | cross-sectional | 2670 | m = 1338, f = 1332 | 6–18 | questionnaire | Average ST of primary and middle school students in Beijing on school days ≤ 2h/d accounted for 93.3%, and that at weekends accounted for 70.0%. | |
Zeng ZP 2021 | China | cross-sectional | 16545 | m = 8344, f = 8201 | 13–22 | questionnaire | Average ST ≤ 2h/d accounted for 81.6% that of boys accounted for 80.9% and that of girls accounted for 82.4%. | |
Cheng L 2016 | China | cross-sectional | 1170 | | 7–11 | questionnaire | Average ST ≤ 2h/d accounted for 85.7%. | |
Hu J 2021 | China | cross-sectional | 882 | m = 437, f = 445 | 6–18 | questionnaire | Average ST < 2h/d accounted for 39.1%. | |
Huang WH 2020 | China | cross-sectional | 12357 | m = 6292, f = 6065 | 12 | questionnaire | Average ST ≥ 2h/d accounted for 18.9%, with that of boys accounted for 18.5% and girls accounted for 19.1%. | |
Lin LZ 2018 | China | cross-sectional | 1889 | | 7–11 | questionnaire | Average ST ≥ 2h/d accounted for 22.9%. | |
Liu WJ 2017 | China | cross-sectional | 2859 | | 7–12 | questionnaire | Average ST ≥ 2h/d on school days accounted for 17.7% and at weekends accounted for 33.6%. | |
Liu ZH 2021 | China | cross-sectional | 1090 | m = 561, f = 529 | 9–12 | questionnaire | Average ST of 8-year-olds ≤ 2h/d accounted for 94.8%. The data for 9-year-olds was 94.2%, for 10-year-olds was 94.6%, and the overall study was 94.4%. | |
Ren TT 2018 | China | cross-sectional | 2644 | m = 1402, f = 1242 | 7–18 | questionnaire | Average ST of Kashgar Uyghur children < 2h/d accounted for 50.1%. Average ST of primary school < 2h/d accounted for 60.2% and that of middle school accounted for 56.2%. The overall weekday ST length < 2h/d accounted for 93.3%, and at weekends accounted for 69.7%. | |
Sun JL 2021 | China | cross-sectional | 1432 | m = 758, f = 674 | 6–16 | questionnaire | Average ST ≥ 2h/d accounted for 44.5%. | |
Gallant 2020 | Canada | cross-sectional | 923 | m = 416, f = 507 | 8–19 | database questionnaire | Average ST of girls ≥ 2h/d accounted for 42.5%, and average ST of boys ≥ 2h/d accounted for 42.3%. | |
Zhang SX 2021 | China | cross-sectional | 5266 | | 6–12 | questionnaire | Average ST of first grade ≥ 2h/d on school days and at weekends accounted for 42.4% and 52.9%, 40.9% and 53.1% in second grade, 44.8% and 60.2% in third grade, 43.1% and 59.1% in fourth grade, 42.2% and 55.3% in fifth grade, and 39.6% and 50.4% in sixth grade. | online learning, TV, tablets/computers/mobile phones |
Stefen Schmidt 2017 | Canada | cross-sectional | 18147 | m = 9243, f = 8904 | 9–12 | questionnaire | Average ST of 6 to 10-year-olds < 2h/d accounted for 79.7%, and that of 11 to 13-year-olds accounted for 40.1%. | |
Wang J 2019 | China | cross-sectional | 1062 | m = 576, f = 486 | 11–19 | questionnaire | Average ST ≥ 2h/d accounted for 20.3%. | |
Bel-Serrat 2019 | 19 European countries | cross-sectional | 1758 | m = 908, f = 850 | 6–9 | database questionnaire | Northern Europe has the longest screen time (1.9 h/d), Eastern European countries have 1.7 h/d and Southern European / Mediterranean countries have the shortest screen time (1.4 h/d). | |
Leonie 2020 | Europe | cross-sectional | 2694 | m = 1387, f = 1307 | 2–18 | database | Average ST was 13.2 h/w for children of 7–8 years old, 14.6 h/w for children of 9–10 years old, 18.4 h/w for children of 11 years old and above, and 13.7 h/w for the whole study population. | |
Miguel 2020 | Spain | cross-sectional | 908 | | 5–14 | database questionnaire | Average ST of children was 2.02 h/d (SD = 1.03). | |
Didier 2017 | Canada | cross-sectional | 1328 | m = 674, f = 654 | 6–11 | database questionnaire | Children's average ST length was 2.3 h/d, using TV (1.6 h/d) and computer (0.7 h/d). | TV, games, learn, chat, emails, surf the Internet |
Jodie 2017 | Canada | cross-sectional | 18147 | | 9–12 | questionnaire | The ST was 4.5 h/d for women and 5.2 h/d for men. | |
Michelle 2019 | The United States | cross-sectional | 11875 | m = 6188, f = 5681 | 9–10 | questionnaire | Children's ST: 1.26 h/d for TV / movies, 0.98 h/d for videos, 1.01 h/d for video games, 0.52 h/d for social media, 0.38 h/d for M-level games. 0.56 h/d for R-rated movies. | TV/movies/ videos, video games, social media |
Amund 2019 | Norway | cross-sectional | 4509 | m = 2128 ,f = 2381 | 11,13, 15,16 | questionnaire | The average ST was 6.1 h/d (SD4.3). | TV, games and other purposes |
Julie 2018 | Europe | cross-sectional | 10696 | m = 5380, f = 5589 | 5–13 | questionnaire | Children's average ST was 106.9m/d, mainly for watching TV. | |
Rubén 2020 | Spain | cross-sectional | 860 | m = 437, f = 423 | 3–16 | questionnaire | Average ST was 2.0 h/d before home confinement, 4.9 h/d during confinement and 4.8 h/d after relaxation of confinement. | online games and learning |
Olga 2021 | Greece | cross-sectional | 1331 | m = 600, f = 731 | 10–12 | questionnaire | Average ST was 1.52 h/d on weekdays and 3.19 h/d at weekends. | TV, computer games |
Nazgol 2019 | Iran | cross-sectional | 23043 | m = 11706, f = 11337 | 6–18 | questionnaire | Average ST was 1.9 h/d (SD1.2), with 59.1% of subjects < 2 hours and 40.9% of subject ≥ 2 hours. | TV, computer games |
Joanna 2020 | Poland | cross-sectional | 14044 | m = 6488, f = 7556 | 13–19 | questionnaire | Subjects ST (h/d): 13-year-old girls 2.5 ± 1.5 and boys 2.7 ± 1.6, 14-year-old girls 2.7 ± 1.5 and boys 3.0 ± 1.6. | |
Napoleón 2017 | Spain | cross-sectional | 6487 | m = 3269, f = 3218 | 6–9 | questionnaire | The average ST of subjects was 2.5 ± 1.4 h/d. | |
Chiaki 2017 | Japan | cross-sectional | 426 | | 6–12 | questionnaire | The children with an average ST length of 146 ± 80m/d and > 2h/d accounted for 59.8%. | games, TV, videos |
Panagiotis 2021 | Athens | cross-sectional | 91 | m = 39, f = 52 | 8–12 | questionnaire | Average ST in three study groups was 2.3 h/d, 3.0 h/d, 2.7 h/d. | |
Ye SY 2018 | China | cross-sectional | 1063 | m = 510, f = 553 | 8–19 | questionnaire | Average ST on weekdays was 1.86 h/d for boys and 1.33 h/d for girls; 7.12 h/ d for boys and 5.86 h/d for girls at weekends. | TV, mobile phones or tablets, computers for entertainment and learning purposes |
Diane 2021 | Canada | cross-sectional | 73 | | 6–12 | questionnaire | Average ST was 5.9 h/d. | |
Li PH 2016 | China | cross-sectional | 5876 | m = 2816, f = 3060 | 11–15 | questionnaire | Average ST of 11-year-old children on school days was 1.85 h/d, and that at weekends was 4.80 h/d. Average ST of 13-year-old children on school days was 1.59 h/d and that at weekends was 5.24 h/d. | games, TV, computers |